The present invention relates to a device for rotating a valve that forcibly produces rotations of a gas changing valve in an internal combustion engine. This valve rotation is in the course of the gas changing valve""s opening and closing movements. The valve comprises a basic body surrounding the valve shaft, that is connected with the shaft in a force-transmitting manner. This basic body has a plurality of pockets oriented in a circumferential or peripheral direction for receiving roller bodies initially tensioned by tangential springs. In addition, this design also contains a cover which acts as a valve spring support. There is also a cup spring clamped between the basic body and the cover that serves as a force transmitter or energy reservoir for the valve rotations.
The components xe2x80x9cbasic bodyxe2x80x9d and xe2x80x9ccoverxe2x80x9d of the device are produced in one or more stages by a cold flow pressing method. This method requires complicated dies whose useful life is determined by the material used and the required reshaping forces. The cold flow pressing process has to be performed in many steps with intermediate annealing. After this process, cutting steps are still required to produce a plurality of defined functional surfaces. This result means that there are high production costs for the device components. Thus, the aim of this invention is to reduce the manufacturing costs without causing any negative effects on the rigidity, function and duration of the useful life of the device.
The invention relates to a device for rotating a valve that has a basic body that embraces the valve shaft. The basic body has a plurality of pockets oriented in a circumferential or peripheral direction, With this invention, the basic body and cover of the device can be produced by a simpler production method and at a more favorable cost. In this case, the basic body and the cover of a device are made of re-formed sheet metal parts.
The basic body and the cover, which are made of a steel sheet, limit the re-shaping process to the important functional surfaces such as the cone, the cup spring support, and the ball raceway. The functional surfaces that are of secondary importance, are replaced by smaller individual surfaces, which are uniformly distributed over the circumference and slightly bent. Thus, it is possible to reduce the required cutting procedures to very few operations for adjusting defined measurements of the finished product.
The number of necessary requirements and the cost with respect to the tool for producing the pressed metal sheet components can thereby be substantially reduced. The recesses of the roller body pockets are slightly pressed only proportionally. Thus, this design results in a considerable cost savings.
The pockets can be formed in different ways, either similar to the shape commonly used at the present time, or by lining up a plurality of different bevels. The gaps between the pockets, which are conditioned by the process, are closed by simple construction elements which maintain the tangential springs within the pockets in their positions at the same time. These construction elements, which can be pins or stops, can also be connected in the form of a ring and combined to form one single component.
This design ensures a substantially enhanced exchange of lubricant by the openings between the ball pockets.
The stiffenings required for the stability of the pocket rim of the basic body versus the cone are shaped into the sheet metal body. The basic body has additional stability provided by grooves or steps extending all around.
The material consumption and thus also the moving components are substantially reduced in this manner. The material used should be suitable for the hardening process and at the same time well-suited also for the re-forming process,
The cover is produced in the form of a simple pressed component as well. The steps extending all around are not complete in this connection, but produced only as individual bent tongues or steps uniformly distributed over the circumference.
The device for rotating a valve can be closed after its individual components have been assembled by bending individual tongues against the basic body.
Starting with a flat disk, the basic body is produced by molding the cone and pressing all pockets into its flange-like rim. As the pockets are being pressed in, their ends are separated from the beginning of the next pocket, so that a gap is produced. The gaps may be narrower than the bridges used before, which means that either the pitch circle and thus the construction space can be selected smaller with the same load, or the size of the rolling bodies, such as balls can be selected larger.
Simple construction elements can be used as stop means for the tangential springs in the pockets. These construction elements prevent the springs from slipping. This result can be realized by mounting a separate sheet metal ring with stop tongues reaching into the pockets.
After the balls, the tangential springs, and their holding components have been mounted, the cover is positioned after the cup spring has been put into place, and then fixed by only bending over individual segments along the circumference.